Surface Corrosion
A metal surface can be imagined as a collection of pairs of positive anodes (potential 1) and negative cathodes (potential 2).
The corrosion process takes place when the electrons can flow from the anode to the cathode, and the positive and negative ions in an electrolyte (e.g. the moisture of the atmosphere) can neutralise their charge.
The flow of electrons and ions forms a closed circuit.
The flow of current leads to a loss of material at the anode; the metal surface corrodes.
Schematic procedure
- Anode (potential 1)
- Cathode (potential 2)
- Surface corrosion
- Current of electrons and ions
- Metal surface
- Moisture (electrolyte)